1. Field of the Invention
This invention relates to a noise reduction apparatus for eliminating periodic noise in videotape recorders or the like.
2. Description of the Related Art
In videotape recorder devices (hereinafter abbreviated as VTR devices), for example, the rotary head and related components can develop periodic noises. These periodic noises include fluctuations in the chrominance signal phase or changes in the luminance signal level. Such periodic noises can cause a particular portion of the screen to vary in color or brightness over a specific range. These phenomena have not been generally considered a result of noises, but, in most cases, of the signal themselves.
The VTR device is provided with various noise reduction devices for noise removal. However, those noise reduction devices are for removing random noises rather than periodic noises.